Technical Field
The present invention relates to a monitoring camera device, a monitoring system, which has the monitoring camera device, a mask processing method and a mask processing program which mask part of a video image to protect privacy.
Related Art
Conventionally, monitoring cameras which capture images of monitoring objects and perform mask processing on regions related to privacy in monitoring video images are known. Further, among these monitoring cameras, there is a monitoring camera which captures an image of a monitoring object while changing an image capturing range. By driving the monitoring camera in a tilt direction and a pan direction by a camera rotating table, the image capturing range can be moved in upper and lower directions and left and right directions and the image capturing range can be enlarged and reduced by a zoom function of an optical system of the monitoring camera.
Mask processing is performed on a monitoring video image using a function of hardware of the monitoring camera. In this case, due to limitation of hardware resources, the number of regions which can be set as mask regions to a monitoring video image is limited. Therefore, when the number of regions which need to be subjected to mask processing in the monitoring video image exceeds a predetermined number, it is not possible to perform mask processing on part of the regions.
Further, when an image capturing range of the monitoring camera which captures an image of a monitoring object while changing the image capturing range by panning, tilting and zooming operations (PTZ operation) changes, the number of regions which need to be subjected to mask processing included in a monitoring video image also changes, and the number of the regions included in the monitoring video images may exceed the predetermined number or go below the predetermined number.
JP 2001-69494 A discloses a technique which sets mask regions of a monitoring camera through a personal computer, and the personal computer cannot keep up with processing when the number of regions which need to be subjected to mask processing is too high and, therefore, has a function of counting the number of regions which need to be subjected to mask processing and not permitting the setting of the mask processing when the number of regions which need to be subjected to mask processing exceeds the predetermined number. Further, it is also disclosed that a plurality of privacy zones is covered by one mask so as to reduce the number of regions which need to be subjected to the mask processing. Furthermore, it is also disclosed that, when a plurality of mask regions is included in one screen, transformation is performed to obtain one enlarged mask region including these mask regions and mask processing is performed.